1. Field of the Invention
The invention concerns a tool for the formation of a pretzel blank from a strand of dough. The invention concerns, moreover, a process for the production of a pretzel blank from a dough strand utilizing this tool. Finally, the invention concerns an installation designed to make use of this tool.
2. Discussion of the Related Art
Known (European patent application 0 382 219) is a method for conveying preprepared dough strands between a receiving station, a knot-forming station and a releasing station, the ends of each dough strand being moved toward one another between the receiving station and the knot-forming station and the middle part and side portions of the dough strand dropped down below the ends to form a curved loop. At the knot-forming station this loop is rotated 360.degree. with the aid of two brush rollers. The middle part and the end portions are then tilted upward into a horizontal position. The ends of each strand of dough, then dropped down, are caught between the flanks of two U-shaped, inwardly folded flanks of two grab belts, between the receiving station and the releasing station, and carried along in the direction in which the conveyer moves. This is supposed to permit a high output of pieces per unit of time as well as the delivery of dough strands to the receiving station at irregular intervals. This method for the formation of a pretzel blank requires however a lot of complicated machinery and is consequently liable to stoppages; in addition, the rotating brush rollers and/or dropping down or manual removal of the pretzel blanks from the conveyer belt do not reliably ensure the production of an always uniform pretzel blank.
A further known method (DE-OS 4,032,466) lays a strand of dough over a vertical, semicircular dough-strand holder. The ends of the dough strand are then seized and the adjacent end segments twisted together. The middle portion of the dough strand is then flipped into a horizontal position upon the dough strand ends. The dough strand ends, held in place on a horizontal support, are thereby moved outward and away from the central plane of the middle part of the dough strand, which lies on the dough strand holder. The dough strand holder, standing upright, is then rotated along with the middle part of the dough strand by 360.degree., to be flipped then into the horizontal position. This sequence, taking place in an essentially vertical direction, can easily produce a stretching or tearing of the strand of dough. Furthermore, in this case, too, the production of a uniform or even pretzel shape is not always assured.
Other machines for making pretzels are known (U.S. Pat. Nos. 1,669,277, 1,142,533) in which holding or gripping devices lay a dough strand over its ends on a flat processing plate and thus curl it into a pretzel shape around projecting forming pegs which pierce the processing plate at right angles. This necessarily produces pulling forces capable of reducing the quality of the dough structure. To move the curled dough strand further along off the processing plate, particularly to release it, the plate and the forming pegs must be designed to move toward each other, which requires additional drive mechanisms. Moreover, a precise implementation or maintenance of the desired or curved pretzel shape is not thus guaranteed.